The present invention relates to a shaft sealing apparatus suitable for sealing a gap between two members which rotate relative to each other, for example, a gap between a rotation shaft and a member through which the rotation shaft passes, and a pump apparatus and a brake hydraulic pressure control device for a vehicle using the shaft sealing apparatus.
As a power driven pump used in the brake hydraulic pressure control device, for example, there is a pump disclosed in JP2007-278086A. This pump employs a well-known inner gear pump.
The pump disclosed in JP2007-278086A is driven by the rotation shaft and configured to perform a double-sealing operation using a first seal part constituted by a shaft sealing apparatus and a second seal part constituted by an oil seal in order to prevent introduced brake fluid from being leaked to the outside. In this case, the first seal part is considered to be used when a pressure is applied to an inner liquid chamber and permits micro-leakage.
The brake fluid leaked through the first seal part is collected in an intermediate chamber formed between the first seal part and the second seal part. The oil seal of the second seal part is adapted to prevent the collected brake fluid from being leaked from the intermediate chamber.
Further, the shaft sealing apparatus constituting the first seal part is incorporated in a plug which closes an opening of the pump accommodation chamber. In addition, the shaft sealing apparatus is rotationally locked so that it can be prevented from co-rotating with the rotation shaft which is used for driving the pump and passes through the plug.